Ah, your assets (photos) should not be on the same server as your Discourse install in cases like that… and yes you could be in for a world of hurt if your computer gets damaged/fails, gets stolen, motherboard takes out both drives (it happens!) etc etc.
You should be using a cloud storage solution like Amazon S3. You’ll have more available bandwidth for your users when they upload/download simultaneously as well as built-in fault tolerance. You can even go a step further and periodically backup assets on to Amazon Glacier. And/or you could setup home box to keep a copy of what’s in S3 as well.
The great news is that discourse supports S3..
So, move your Discourse install onto a VPS (with or without SSL, up to you), configure S3 and feast your eyes on the awesomeness.
Lastly, you can also configure your Discourse installation to backup to S3 as well.